Water source machine

Abstract

The present invention provides a water source machine, which includes an indoor unit and an outdoor unit. The outdoor unit includes a compressor, a plate heat exchanger, a four-way valve, a first temperature sensor for detecting the inlet water temperature during heating, and a second temperature sensor for detecting the refrigerant temperature on the outlet side of the plate heat exchanger during heating. The controller is configured to: during heating, when the detection value of the first temperature sensor reaches the upper limit value of the first preset water temperature, control the first water flow switch to perform detection; when the detection value of the first temperature sensor reaches the lower limit value of the first preset water temperature, control the second water flow switch to perform detection and adjust the refrigerant temperature on the outlet side of the plate heat exchanger based on the detection value of the second temperature sensor. The water source machine of the present application can detect the lower limit value of the water flow of the unit by selecting a suitable water flow switch according to different inlet water temperatures, effectively reducing the possibility of the outdoor plate heat exchanger being damaged by freezing under low-temperature heating conditions and improving the operation reliability of the low-temperature heating system.

Description

Technical Field

[0001] The present invention relates to the technical field of air-conditioning equipment, and in particular to a water source machine. Background Art

[0002] With the development of water source machine technology, the operating range of heating conditions has continued to expand, especially the demand for low-temperature heating conditions has increased, and the ability to operate at lower temperatures is required. In order to ensure a good heat exchange rate, the heat exchange temperature difference between the refrigerant and water must be large to meet the demand. Under low-temperature heating conditions, due to the low ambient temperature, the water inlet temperature is already low. If the heat exchange temperature difference between the refrigerant and water increases, the refrigerant temperature must be lower, resulting in the refrigerant temperature being below 0°C. There is a risk of the outdoor unit plate heat exchanger (referred to as the outdoor plate heat exchanger) being frozen. The lower the water temperature, the greater the risk of the outdoor plate heat exchanger being frozen.

[0003] In the prior art, the lower limit of the water inlet temperature of the water source machine during heating is 10°C. In order to make the water inlet temperature reach 5°C and expand the operating range of the water source machine under low-temperature heating conditions, the traditional practice is to add antifreeze to the outdoor plate heat exchanger or increase the water flow rate to prevent the outdoor plate heat exchanger from freezing during low-temperature heating.

[0004] Adding antifreeze is not economical, and after replacing the circulating water, antifreeze needs to be added again, which is inconvenient for maintenance.

[0005] To increase water flow, existing water source units typically incorporate a water flow switch on the water inlet pipe of the outdoor heat exchanger to ensure the water flow rate does not drop too low. This water flow switch has a large cutoff value. For example, when the lower limit of the water inlet temperature is 10°C during heating, the cutoff value of this water flow switch is typically 0.55 times the rated water flow rate. However, this cutoff value does not meet the system's operational reliability at a water temperature of 5°C, and there is still a risk of the outdoor heat exchanger freezing. A water flow switch with a larger cutoff value, such as 1.2 times the rated water flow rate, is needed to further increase the water flow rate and reduce the risk of heat exchanger freezing. While this approach can ensure system operational reliability at a water temperature of 5°C, not all low-temperature heating conditions require a large water flow rate. For example, low-load operation requires a smaller water flow rate. If the water flow switch is designed with a large cutoff value, it will result in excessive pump energy consumption during partial load operation, resulting in energy waste.

[0006] Based on this, how to further expand the operating range of the water source machine's heating conditions so that it can operate at lower temperatures, effectively reduce the possibility of outdoor unit panels being frozen, ensure system operation reliability, and reduce energy waste has become a technical problem that needs to be solved urgently. Summary of the invention

[0007] The present invention provides a water source machine, which can solve the problems in the prior art that the operating range of the water source machine under the heating condition is limited, the system operation reliability is poor during low-temperature heating, and it is not conducive to energy conservation.

[0008] In some embodiments of the present application, a water source machine is provided, which includes an indoor unit and an outdoor unit. An air-side stop valve and a liquid-side stop valve are connected between the indoor unit and the outdoor unit. It is characterized in that the outdoor unit includes:

[0009] A compressor;

[0010] A plate heat exchanger, which includes a refrigerant flow channel and a water flow channel. The first end of the refrigerant flow channel is connected to the liquid-side stop valve, and an electronic expansion valve is provided between the first end and the liquid-side stop valve. A first water flow switch and a second water flow switch are provided on the water inlet side of the water flow channel, and the disconnection value of the first water flow switch is less than the disconnection value of the second water flow switch;

[0011] A four-way valve, whose port 1 is connected to the air-side stop valve, port 2 is connected to the compressor discharge port, port 3 is connected to the second end of the refrigerant flow channel, and port 4 is connected to the compressor suction port;

[0012] A first temperature sensor, which is used to detect the inlet water temperature when the water source machine is heating;

[0013] A second temperature sensor, which is used to detect the refrigerant temperature on the outlet side of the plate heat exchanger when the water source machine is heating;

[0014] A controller, which is configured to: when the detection value of the first temperature sensor reaches the upper limit value of the first preset water temperature during the heating of the water source machine, control the first water flow switch to detect; when the detection value of the first temperature sensor reaches the lower limit value of the first preset water temperature, control the second water flow switch to detect and adjust the refrigerant temperature on the outlet side of the plate heat exchanger based on the detection value of the second temperature sensor; when the detection value of the first temperature sensor reaches the lower limit value of the second preset water temperature, control the water source machine to stop, and the second preset water temperature is less than the first preset water temperature.

[0015] In the water source machine of the present application, by providing a first water flow switch and a second water flow switch with different disconnection values on the water inlet side of the water flow channel of the outdoor plate heat exchanger, the disconnection value of the first water flow switch is smaller, and the disconnection value of the second water flow switch is larger. When the water source machine is heating, the first temperature sensor detection value, that is, the inlet water temperature detection value, is used to determine the first water flow switch and the second water flow switch. When the detection value of the first temperature sensor reaches the upper limit value of the first preset water temperature, that is, the detected inlet water temperature is relatively high, the first water flow switch is controlled to detect, and the action signal of the first water flow switch is used to detect the lower limit value of the unit water flow; when the detection value of the first temperature sensor reaches the lower limit value of the first preset water temperature, that is, the detected inlet water temperature is relatively low, the second water flow switch is controlled to detect, that is, the action signal of the second water flow switch is used to detect the lower limit value of the unit water flow, and based on the detection value of the second temperature sensor, the refrigerant temperature on the outlet side of the outdoor unit plate heat exchanger is adjusted; when the detection value of the first temperature sensor reaches the lower limit value of the second preset water temperature, the water source machine is controlled to stop, and the second preset water temperature is less than the first preset water temperature; thus, anti-freezing treatment of the plate heat exchanger is achieved. Then, the present application can select a suitable water flow switch according to different inlet water temperatures to detect the lower limit value of the unit water flow, and at the same time, it can effectively reduce the possibility of the outdoor plate heat exchanger being damaged in the low-temperature heating condition, thereby solving the problems in the prior art that only one water flow switch is provided, resulting in a limited operating range of the water source machine in the heating condition, poor system operation reliability in low-temperature heating, and being not conducive to energy conservation.

[0016] In some embodiments of the present application, when the detection value of the second temperature sensor reaches the lower limit value of the first preset refrigerant temperature, the controller controls the compressor to prohibit frequency increase and at the same time controls the electronic expansion valve to prohibit valve closing;

[0017] When the detection value of the second temperature sensor reaches the lower limit value of the second preset refrigerant temperature, the controller controls the compressor to force frequency reduction and at the same time controls the electronic expansion valve to force valve opening;

[0018] When the detection value of the second temperature sensor reaches the lower limit value of the third preset refrigerant temperature and lasts for a certain period of time, the controller controls the water source machine to stop;

[0019] When the detection value of the second temperature sensor reaches the upper limit value of the fourth preset refrigerant temperature, the water source machine enters the normal control stage;

[0020] The third preset refrigerant temperature is less than the second preset refrigerant temperature, the second preset refrigerant temperature is less than the first preset refrigerant temperature, the first preset refrigerant temperature is less than the fourth preset refrigerant temperature, the fourth preset refrigerant temperature is less than the inlet water temperature of the water flow channel, and the third preset refrigerant temperature is greater than zero.

[0021] In some embodiments of the present application, the forced frequency reduction rate of the compressor is 1-3 Hz / second, and the forced valve opening rate of the electronic expansion valve is 5-15 steps / second.

[0022] In some embodiments of the present application, the outdoor unit further includes a bypass pipeline. The first end of the bypass pipeline is connected to the pipeline connecting the second port and the compressor exhaust port, and the second end of the bypass pipeline is connected to the pipeline connecting the refrigerant flow channel and the electronic expansion valve. A solenoid valve is provided on the bypass pipeline.

[0023] In some embodiments of the present application, a check valve is further provided on the bypass pipeline, and the check valve is located between the solenoid valve and the second end of the bypass pipeline.

[0024] In some embodiments of the present application, when the detected value of the second temperature sensor reaches the lower limit value of the fifth preset refrigerant temperature, the controller controls the solenoid valve to open intermittently until the detected value of the second temperature sensor reaches the upper limit value of the sixth preset refrigerant temperature, and then the solenoid valve closes;

[0025] When the detected value of the second temperature sensor reaches the lower limit value of the seventh preset refrigerant temperature, the controller controls the solenoid valve to open intermittently, and at the same time, the controller controls the compressor to prohibit frequency increase and the electronic expansion valve to prohibit valve closing;

[0026] When the detected value of the second temperature sensor reaches the lower limit value of the eighth preset refrigerant temperature, the controller controls the solenoid valve to open intermittently, and at the same time, the controller controls the compressor to force frequency reduction and the electronic expansion valve to force valve opening;

[0027] When the detected value of the second temperature sensor reaches the lower limit value of the ninth preset refrigerant temperature and lasts for a certain period of time, the controller controls the water source machine to stop;

[0028] The ninth preset refrigerant temperature is less than the eighth preset refrigerant temperature, the eighth preset refrigerant temperature is less than the seventh preset refrigerant temperature, the seventh preset refrigerant temperature is less than the fifth preset refrigerant temperature, the fifth preset refrigerant temperature is less than the sixth preset refrigerant temperature, the sixth preset refrigerant temperature is less than the inlet temperature of the water flow channel, and the ninth preset refrigerant temperature is greater than zero degree.

[0029] In some embodiments of the present application, the forced frequency reduction rate of the compressor is 1-3 Hz / second, and the forced valve opening rate of the electronic expansion valve is 5-15 steps / second.

[0030] In some embodiments of the present application, the outdoor unit further includes a gas-liquid separator, and the gas-liquid separator is connected between the compressor suction port and the fourth port of the four-way valve.

[0031] In some embodiments of the present application, the outdoor unit further includes an oil separator, and the oil separator is connected between the compressor exhaust port and port two of the four-way valve.

[0032] In some embodiments of the present application, an oil return pipeline is connected between the oil separator and the gas-liquid separator, and a capillary tube is connected to the oil return pipeline. Description of the Drawings

[0033] Figure 1 Shows a schematic structural diagram of a prior art water source machine;

[0034] Figure 2 Shows a schematic structural diagram of the outdoor unit of a prior art water source machine;

[0035] Figure 3 Shows a schematic structural diagram of a water source machine according to Embodiment 1;

[0036] Figure 4 Shows a schematic structural diagram of the outdoor unit of a water source machine according to Embodiment 1;

[0037] Figure 5 Shows a schematic structural diagram of a water source machine according to Embodiment 2;

[0038] Figure 6 Shows a schematic structural diagram of the outdoor unit of a water source machine according to Embodiment 2;

[0039] Figure 7 Shows a schematic structural diagram of a water source machine according to Embodiment 3;

[0040] Figure 8 Shows a schematic structural diagram of the outdoor unit of a water source machine according to Embodiment 3;

[0041] Figure 9 Shows a schematic structural diagram of a water source machine according to Embodiment 4;

[0042] Figure 10 Shows a schematic structural diagram of the outdoor unit of a water source machine according to Embodiment 4.

[0043] Figure 1 、 Figure 2 In the drawings, reference numerals: 10 - outdoor unit; 11 - plate heat exchanger; 12 - water flow channel inlet pipe; S - water flow switch; 20 - indoor unit;

[0044] Figures 3 to 10Reference numerals in the drawings: 1 - outdoor unit; 10 - compressor; 11 - exhaust port; 12 - suction port; 20 - four-way valve; 21 - first four-way valve port; 22 - second four-way valve port; 23 - third four-way valve port; 24 - fourth four-way valve port; 30 - plate heat exchanger; 31 - refrigerant flow channel; 31A - first end of the refrigerant flow channel; 31B - second end of the refrigerant flow channel; 32 - water flow channel; 40 - electronic expansion valve; 50 - gas-side stop valve; 60 - liquid-side stop valve; 70 - first temperature sensor; 80 - second temperature sensor; 90 - bypass pipeline; 100 - solenoid valve; 110 - check valve; 120 - gas-liquid separator; 130 - oil separator; 140 - oil return pipeline; 150 - capillary tube;

[0045] 2 - indoor unit. Detailed implementation manners

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present invention.

[0048] The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0049] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0050] In the present invention, unless otherwise clearly specified or limited, the first feature being “on” or “under” the second feature may include direct contact between the first and second features, or may include indirect contact between the first and second features through additional features therebetween. Moreover, the first feature being “above”, “over” and “on top of” the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being “under”, “below” and “beneath” the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is less than that of the second feature.

[0051] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity and does not in itself indicate the relationship between the various embodiments and / or arrangements discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0052] In the present invention, an air conditioner performs a refrigeration cycle of the air conditioner by using a compressor, a condenser, an expansion valve and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion and evaporation to cool or heat an indoor space.

[0053] A low-temperature and low-pressure refrigerant enters the compressor, and the compressor compresses the refrigerant into a high-temperature and high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process.

[0054] The expansion valve expands the high-temperature and high-pressure liquid-phase refrigerant formed by condensation in the condenser into a low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the expansion valve and returns the refrigerant gas in a low-temperature and low-pressure state to the compressor. The evaporator can achieve a refrigeration effect by using the latent heat of evaporation of the refrigerant to perform heat exchange with the material to be cooled. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space.

[0055] The outdoor unit of the air conditioner refers to the part of the refrigeration cycle including the compressor and the outdoor heat exchanger. The indoor unit of the air conditioner includes an indoor heat exchanger, and the expansion valve can be provided in the indoor unit or the outdoor unit.

[0056] The indoor heat exchanger and the outdoor heat exchanger are used as condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner serves as a heater in the heating mode, and when the indoor heat exchanger is used as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0057] The water source multi-connected unit system combines the water source heat pump technology with the air source multi-connected unit system. The cold and heat source side is the same as that of the water source heat pump system, using water as the energy transportation medium, and the indoor side is the same as that of the multi-connected unit system, using refrigerant as the energy transportation medium. The cold and heat sources of the water source multi-connected unit system are usually groundwater, surface water, etc.

[0058] In the prior art, the structure of the water source unit is as Figure 1 shown, which includes an outdoor unit 10 and an indoor unit 20. The structure of the outdoor unit 10 is as Figure 2 shown. In the prior art, the lower limit value of the inlet water temperature of the water source unit during heating is 10°C. In order to enable the inlet water temperature to reach 5°C to expand the operating range of the water source unit under low-temperature heating conditions, the traditional common practice is to increase the water flow rate to prevent the outdoor plate heat exchanger from freezing during low-temperature heating.

[0059] Specifically, the existing water source unit usually configures a water flow switch S on the water inlet pipe 12 of the water flow channel of the plate heat exchanger 11 of the outdoor unit 10 to ensure that the water flow rate will not be too low. This water flow switch S has a relatively large disconnection value. Taking the lower limit value of the inlet water temperature of the prior art water source unit during heating as 10°C as an example, the disconnection value of this water flow switch is usually 0.55 times the rated water flow. However, the disconnection value of this water flow switch cannot meet the operating reliability of the system during heating with a water temperature of 5°C, and there is still a risk of freezing of the outdoor unit plate heat exchanger. It is necessary to replace it with a water flow switch with a larger disconnection value, such as a water flow switch with a disconnection value of 1.2 times the rated water flow, to further increase the water flow rate and reduce the risk of freezing of the plate heat exchanger. Although this can meet the operating reliability of the system during heating with a water temperature of 5°C, not all low-temperature heating operating conditions require a large water flow rate. For example, the water flow rate required during low-load operation of the system is relatively small. If a large water flow rate disconnection value is used for the water flow switch at the beginning of the design, it will cause excessive energy consumption of the water pump during partial load operation, resulting in the problem of energy waste.

[0060] In the embodiment of the present application, a water source unit is provided. Refer to Figures 2 to 10, including an indoor unit and an outdoor unit. A gas-side stop valve and a liquid-side stop valve are connected between the indoor unit and the outdoor unit. The outdoor unit includes a compressor, a plate heat exchanger, a four-way valve, a first temperature sensor, a second temperature sensor, and a controller. The controller is configured to: when the water source machine is in heating mode, when the detection value of the first temperature sensor reaches the upper limit value of the first preset water temperature, control the first water flow switch to detect; when the detection value of the first temperature sensor reaches the lower limit value of the first preset water temperature, control the second water flow switch to detect and adjust the refrigerant temperature at the outlet side of the plate heat exchanger based on the detection value of the second temperature sensor; when the detection value of the first temperature sensor reaches the lower limit value of the second preset water temperature, control the water source machine to stop, and the second preset water temperature is less than the first preset water temperature; thereby realizing the anti-freezing of the plate heat exchanger. In the embodiment of the present application, the water source machine can solve the above problems existing in the prior art water source machine, further expand the heating operating range of the water source machine, enable it to operate in heating mode at a lower ambient temperature, effectively reduce the possibility of the outdoor unit plate heat exchanger being damaged by freezing, ensure the reliability of the system operation, and at the same time reduce energy waste.

[0061] The specific structure and working principle of the water source machine of the present application will be described in detail below through specific embodiments.

[0062] Embodiment 1

[0063] Figure 3 Fig. shows the structural schematic diagram of the water source machine according to Embodiment 1. Figure 4 Fig. shows the structural schematic diagram of the outdoor unit of the water source machine according to Embodiment 1. As Figure 3 and Figure 4 shown, a water source machine in this embodiment includes an outdoor unit 1 and a plurality of indoor units 2. In this embodiment, a one-to-two water source machine composed of two indoor units 2 and one outdoor unit 1 is taken as an example for description, but it is not limited to this form of water source machine.

[0064] Among them, the outdoor unit 1 includes a compressor 10, a four-way valve 20, a plate heat exchanger 30, an electronic expansion valve 40, a liquid-side stop valve 60, and a gas-side stop valve 50, which are connected in sequence according to the refrigerant flow to form a loop, and the indoor unit 2 is connected between the liquid-side stop valve 60 and the gas-side stop valve 50.

[0065] The compressor 10 is provided with a compressor exhaust port 11 and a compressor suction port 12, which are used to compress the refrigerant into a gaseous refrigerant in a high-temperature and high-pressure state and discharge it through the compressor exhaust port 11.

[0066] Plate heat exchanger 30, which includes a refrigerant flow channel 31 and a water flow channel 32. The refrigerant flow channel 31 has a first end 31A and a second end 31B of the refrigerant flow channel. The plate heat exchanger 30 is connected to the refrigerant circulation loop of the water source machine through its refrigerant flow channel 31; the water flow channel 32 is connected to the water source as a cold and heat source for water to flow through. When the water source machine works, the refrigerant and water exchange heat in the plate heat exchanger 30. The water source is usually groundwater, surface water, etc. The first end 31A of the refrigerant flow channel is connected to the liquid side stop valve 60 through a pipeline, and the electronic expansion valve 40 mentioned above is provided on the connecting pipeline between the first end 31A of the refrigerant flow channel and the liquid side stop valve 60. A first water flow switch S1 and a second water flow switch S2 are provided on the water inlet side of the water flow channel 32. The disconnection value of the first water flow switch S1 is less than the disconnection value of the second water flow switch S2. The water flow switch is used for the water circulation control, water inlet and outlet control, water heating control, water pump switch control, solenoid valve on-off control, or water outlet power-off and water outlet power-on control of electric water heaters, solar water heaters, air conditioners, and other water systems. It is a sensor device that converts water flow into a switch-type electrical signal when a certain flow rate is reached. Its disconnection value is the lower limit water flow rate. A large disconnection value means a high lower limit water flow rate, and a small disconnection value means a low lower limit water flow rate. The straight arrow on the left side of the plate heat exchanger 30 indicates the refrigerant flow direction during heating, and the straight arrow on the right side indicates the water flow direction.

[0067] The four-way valve 20 has four ports, namely the four-way valve port one 21, the four-way valve port two 22, the four-way valve port three 23, and the four-way valve port four 24. The four-way valve port one 21 is connected to the gas side stop valve 50, the four-way valve port two 22 is connected to the compressor discharge port 11, the four-way valve port three 23 is connected to the second end 31B of the refrigerant flow channel, and the four-way valve port four 24 is connected to the compressor suction port 12.

[0068] The first temperature sensor 70 is provided on the water inlet side of the water flow channel 32, and it is used to detect the water inlet temperature of the water flow channel when the water source machine is heating, that is, the water source inlet temperature.

[0069] The second temperature sensor 80 is provided on the second end 31B of the refrigerant flow channel, and it is used to detect the refrigerant temperature flowing out of the refrigerant flow channel 31 when the water source machine is heating, that is, the refrigerant temperature on the outlet side of the plate heat exchanger 30.

[0070] In this embodiment, the controller is specifically configured as follows: When the water source machine is heating, when the detection value T of the first temperature sensor W reaches the upper limit value of the first preset water temperature T 预设水1 , control the first water flow switch S1 to detect, that is, use the action signal of the first water flow switch S1 to detect the lower limit value of the unit water flow rate; when the detection value T of the first temperature sensor W reaches the first preset water temperature T 预设水1When the value reaches the lower limit value, control the first water flow switch S1 to detect, that is, use the action signal of the first water flow switch S1 to detect the lower limit value of the water flow of the unit; when the detection value T of the first temperature sensor W reaches the second preset water temperature T 预设水2 at the lower limit value, control the water source machine to stop.

[0071] It should be noted that if T 预设水1 is a numerical range, when the detection value T of the first temperature sensor W reaches the upper limit value of the first preset water temperature T 预设水1 , then T W is not less than any value within this numerical range. If T 预设水1 is a specific numerical point, then its upper limit value is itself; similarly, if T 预设水1 is a numerical range, when the detection value T of the first temperature sensor W reaches the lower limit value of the first preset water temperature T 预设水1 , then T W is not greater than any value within this numerical range. If T 预设水1 is a specific numerical point, then its lower limit value is itself. For the following descriptions that reach such descriptions, the same explanation applies and will not be repeated.

[0072] As a specific embodiment, when the inlet water temperature ≥ 10°C, in this working condition, due to the relatively high inlet water temperature, although the refrigerant temperature flowing out of the plate heat exchanger 30 during heating is less than 10°C, it will not be lower than 0°C, and the plate heat exchanger 30 will not freeze. Then, the first water flow switch S1 with a smaller disconnection value can be used, such as 0.55 times the rated water flow, which ensures the reliability of the system operation; when the inlet water temperature < 10°C, such as 5°C, due to the relatively low inlet water temperature, the refrigerant temperature flowing out of the plate heat exchanger 30 during heating will be less than 5°C and even lower than 0°C, and the possibility of the plate heat exchanger 30 freezing is high. Then, the second water flow switch S2 with a larger disconnection value is used, such as 1.2 times the rated water flow, that is, switched to a high water flow water flow switch, reducing the possibility of the plate heat exchanger 30 being damaged by freezing and ensuring the reliability of the system operation; at the same time, selecting a water flow switch with an appropriate disconnection value according to different inlet water temperatures can avoid the problem of energy inefficiency caused by selecting a water flow switch with an overly large disconnection value at the beginning of the existing technology.

[0073] To effectively ensure the reliability of the system operation when the detection value T of the first temperature sensor W reaches the lower limit value of the first preset water temperature T 预设水1 , in addition to switching to the second water flow switch S2 with a high water flow for detection, it is also necessary to adjust the refrigerant temperature when flowing out of the plate heat exchanger 30 based on the detection value T of the second temperature sensor g .

[0074] Specifically, when the detected value T of the second temperature sensor g (i.e., the refrigerant temperature at the outlet side of the plate heat exchanger 30) reaches the lower limit value of the first preset refrigerant temperature T 预设媒1 , that is, T g ≤T 预设媒1， At this time, the controller controls the compressor 10 to prohibit frequency increase, and at the same time controls the electronic expansion valve 40 to prohibit valve closing, that is, prohibits reducing the opening. For example, the compressor 10 maintains the current operating frequency or reduces the frequency, and the electronic expansion valve 40 maintains the current opening or increases the opening. By prohibiting the compressor 10 from increasing frequency and the electronic expansion valve 40 from closing the valve, the reduction of the suction pressure Ps can be restricted, so as to achieve the purpose of restricting the reduction of the refrigerant temperature, and thus the anti-freezing effect of the plate heat exchanger can be effectively improved.

[0075] If the detected value T of the second temperature sensor is further reduced at this time g , when the detected value T of the second temperature sensor g reaches the lower limit value of the second preset refrigerant temperature T 预设媒2 , that is, T g ≤T 预设媒2 , at this time, the controller controls the compressor to force the frequency to decrease, and at the same time controls the electronic expansion valve to force the valve to open. By forcing the compressor 10 to reduce the frequency and the electronic expansion valve 40 to open the valve, the suction pressure Ps can be increased, so as to increase the refrigerant temperature flowing out of the plate heat exchanger 30 and achieve the purpose of preventing the plate heat exchanger from freezing.

[0076] When the detected value T of the second temperature sensor g reaches the lower limit value of the third preset refrigerant temperature T 预设媒3 , that is, T g ≤T 预设媒3 , and the duration is t, at this time, the controller controls the water source machine to stop. Among them, t takes a value of 90s.

[0077] In the stage of forced frequency decrease and forced valve opening increase, if the detected value T of the second temperature sensor g is well controlled, and T g >T 预设媒2 , it enters the stage of prohibiting frequency increase and prohibiting valve opening decrease. If the detected value T of the second temperature sensor g is further increased, when the detected value T of the second temperature sensor g reaches the upper limit value of the fourth preset refrigerant temperature T 预设媒4 , that is, T g ≥T 预设媒4 it enters the normal operation stage of the unit.

[0078] Among them, the above-mentioned third preset refrigerant temperature T 预设媒3 is less than the second preset refrigerant temperature T 预设媒2 , and the second preset refrigerant temperature T 预设媒2 is less than the first preset refrigerant temperature T预设媒1 , the first preset refrigerant temperature T 预设媒1 is less than the fourth preset refrigerant temperature T 预设媒4 , the fourth preset refrigerant temperature T 预设媒4 is less than the inlet water temperature of the water flow path 3-2, and the third preset refrigerant temperature T 预设媒3 is greater than zero. That is, 0 < T 预设媒3 <T 预设媒2 <T 预设媒1 <T 预设媒4 < the detection value T of the first temperature sensor W。

[0079] The forced frequency reduction rate of the compressor 10 is defined as H, and the forced valve opening rate of the electronic expansion valve 40 is defined as E. Among them, the value range of H is preferably 1-3 Hz / s, and the value range of E is preferably 5-15 steps / s.

[0080] Embodiment 2

[0081] Figure 5 shows a schematic structural diagram of a water source machine according to Embodiment 1, Figure 6 shows a schematic structural diagram of the outdoor unit of the water source machine according to Embodiment 1. As Figure 5 and Figure 6 shown, a water source machine in this embodiment includes an outdoor unit 1 and a plurality of indoor units 2. In this embodiment, a one-to-two water source machine composed of two indoor units 2 and one outdoor unit 1 is taken as an example for illustration, but it is not limited to this form of water source machine.

[0082] Among them, the outdoor unit 1 includes a compressor 10, a four-way valve 20, a plate heat exchanger 30, an electronic expansion valve 40, a liquid-side stop valve 60 and a gas-side stop valve 50, which are connected in sequence according to the refrigerant flow to form a loop, and the indoor unit 2 is connected between the liquid-side stop valve 60 and the gas-side stop valve 50.

[0083] The compressor 10 is provided with a compressor exhaust port 11 and a compressor suction port 12, which are used to compress the refrigerant into a gaseous refrigerant in a high-temperature and high-pressure state and discharge it through the compressor exhaust port 11.

[0084] Plate heat exchanger 30, which includes a refrigerant flow channel 31 and a water flow channel 32. The refrigerant flow channel 31 has a first end 31A and a second end 31B of the refrigerant flow channel. The plate heat exchanger 30 is connected to the refrigerant circulation loop of the water source machine through its refrigerant flow channel 31; the water flow channel 32 is connected to the water source as a cold and heat source for water to flow through. When the water source machine works, the refrigerant and water exchange heat in the plate heat exchanger 30. The water source is usually groundwater, surface water, etc. The first end 31A of the refrigerant flow channel is connected to the liquid side stop valve 60 through a pipeline, and the electronic expansion valve 40 as described above is provided on the connecting pipeline between the first end 31A of the refrigerant flow channel and the liquid side stop valve 60. The first water flow switch S1 and the second water flow switch S2 are provided on the water inlet side of the water flow channel 32, and the disconnection value of the first water flow switch S1 is less than the disconnection value of the second water flow switch S2. The straight arrow on the left side of the plate heat exchanger 30 indicates the refrigerant flow direction during heating, and the straight arrow on the right side indicates the water flow direction.

[0085] The four-way valve 20 has four ports, namely the four-way valve port one 21, the four-way valve port two 22, the four-way valve port three 23, and the four-way valve port four 24. The four-way valve port one 21 is connected to the gas side stop valve 50, the four-way valve port two 22 is connected to the compressor discharge port 11, the four-way valve port three 23 is connected to the second end 31B of the refrigerant flow channel, and the four-way valve port four 24 is connected to the compressor suction port 12.

[0086] The first temperature sensor 70 is provided on the water inlet side of the water flow channel 32, and it is used to detect the water inlet temperature of the water flow channel when the water source machine is heating, that is, the water source inlet temperature.

[0087] The second temperature sensor 80 is provided on the second end 31B of the refrigerant flow channel, and it is used to detect the refrigerant temperature flowing out of the refrigerant flow channel 31 when the water source machine is heating, that is, the refrigerant temperature flowing out of the plate heat exchanger 30.

[0088] In this embodiment, the outdoor unit 1 further includes a bypass pipeline 90. The first end of the bypass pipeline 90 is connected to the connecting pipeline between the four-way valve port two 22 and the compressor discharge port 11, and the second end of the bypass pipeline 90 is connected to the connecting pipeline between the refrigerant flow channel 31 and the electronic expansion valve 40. The bypass pipeline 90 is provided with an electromagnetic valve 100.

[0089] Different from the first embodiment, in this embodiment, the controller is specifically configured as follows: when the detection value T of the first temperature sensor W reaches the lower limit value of the first preset water temperature T 预设水1 and the second water flow switch S2 is used to detect the water flow rate, the outlet side refrigerant temperature of the plate heat exchanger 30 is adjusted in the following manner.

[0090] Specifically, when the detection value T of the second temperature sensor g reaches the fifth preset refrigerant temperature T 预设媒5When the value reaches the lower limit, the controller controls the solenoid valve 100 to open intermittently for a time interval of t1 and an on-duration of t2 until the detected value T of the second temperature sensor g reaches the upper limit of the sixth preset refrigerant temperature T 预设媒6 , the solenoid valve 100 closes; by intermittently opening the solenoid valve 100, the high-pressure refrigerant can be bypassed through the bypass pipeline 90 to the inlet side of the plate heat exchanger 30, which can increase the refrigerant temperature entering the plate heat exchanger 30, thereby increasing the refrigerant temperature flowing out of the plate heat exchanger, that is, the refrigerant temperature on the outlet side of the plate heat exchanger 30, and reducing the risk of the plate heat exchanger being frozen.

[0091] If the detected value T of the second temperature sensor is further reduced at this time g , for example, T g reaches the lower limit of the seventh preset refrigerant temperature T 预设媒7 , the controller controls the solenoid valve 100 to open intermittently with an interval time of t1 and an on-duration of t2, and at the same time controls the compressor 10 to prohibit frequency increase and the electronic expansion valve 40 to prohibit valve closing. By prohibiting the compressor 10 from increasing frequency and the electronic expansion valve 40 from closing, the suction pressure Ps can be restricted from decreasing, thereby achieving the purpose of restricting the refrigerant temperature from decreasing.

[0092] If the detected value T of the second temperature sensor is further reduced at this time g , for example, T g reaches the lower limit of the eighth preset refrigerant temperature T 预设媒8 , the controller controls the solenoid valve 100 to open intermittently with an interval time of t1 and an on-duration of t2, and at the same time the controller controls the compressor 10 to force frequency reduction and the electronic expansion valve 40 to force valve opening. By forcing the compressor 10 to reduce frequency and the electronic expansion valve 40 to open, the suction pressure Ps can be increased, thereby increasing the refrigerant temperature entering the plate heat exchanger, and further increasing the refrigerant temperature flowing out of the plate heat exchanger, achieving the purpose of preventing the plate heat exchanger from freezing.

[0093] When the detected value T of the second temperature sensor g reaches the lower limit of the ninth preset refrigerant temperature T 预设媒9 and lasts for a certain time t, the controller controls the water chiller to stop. Among them, t is taken as 90 s.

[0094] If the refrigerant temperature is well controlled and the detected value T of the second temperature sensor g rises to reach the upper limit of the seventh preset refrigerant temperature T 预设媒7 , the controller controls the solenoid valve 100 to open intermittently, and at the same time the controller controls the compressor 10 to shift from forced frequency reduction and the electronic expansion valve 40 to forced valve opening to the compressor 10 prohibiting frequency increase and the opening of the electronic expansion valve 40 prohibiting decrease; if the detected value T of the second temperature sensor g is further increased to reach the upper limit of the tenth preset refrigerant temperature T 预设媒10When the upper limit value is reached, the control of the frequency of the compressor 10 and the control to prohibit the change of the opening degree of the electronic expansion valve 40 are exited, and the compressor 10 and the electronic expansion valve 40 are controlled according to the corresponding calculated frequency and valve opening degree. Through the above control, it can be ensured that when the refrigerant temperature entering the plate heat exchanger 30 is relatively low, the solenoid valve 100 is preferentially controlled to prevent the plate heat exchanger from freezing, and the reliable heating performance of the system is ensured.

[0095] Among them, the ninth preset refrigerant temperature is less than the eighth preset refrigerant temperature, the eighth preset refrigerant temperature is less than the seventh preset refrigerant temperature, the seventh preset refrigerant temperature is less than the tenth preset refrigerant temperature, the tenth preset refrigerant temperature is less than the fifth preset refrigerant temperature, the fifth preset refrigerant temperature is less than the sixth preset refrigerant temperature, the sixth preset refrigerant temperature is less than the inlet temperature of the water flow channel, and the ninth preset refrigerant temperature is greater than zero degree, that is, 0 < T 预设媒9 <T 预设媒8 <T 预设媒7 <T 预设媒10 <T 预设媒5 <T 预设媒6 < the detection value T of the first temperature sensor W。

[0096] A check valve 110 is further provided on the bypass pipeline 90. The check valve 110 is located between the solenoid valve 100 and the second end of the bypass pipeline 90. The check valve 110 is configured to only allow the high-pressure refrigerant at the compressor exhaust port 11 to bypass to the plate heat exchanger 30 through the bypass pipeline 90, and cannot bypass from the plate heat exchanger 30 to the compressor 10.

[0097] Embodiment 3

[0098] Figure 7 The structural schematic diagram of the water source machine according to Embodiment 3 is shown, Figure 8 The structural schematic diagram of the outdoor unit of the water source machine according to Embodiment 3 is shown. As Figure 7 and Figure 8 shown, a water source machine in this embodiment includes an outdoor unit 1 and two indoor units 2.

[0099] Among them, the outdoor unit 1 includes a compressor 10, a four-way valve 20, a plate heat exchanger 30, an electronic expansion valve 40, a liquid side stop valve 60, a gas side stop valve 50 and a bypass pipeline 90, and the indoor unit 2 is connected between the liquid side stop valve 60 and the gas side stop valve 50.

[0100] The compressor 10 is provided with a compressor exhaust port 11 and a compressor suction port 12.

[0101] The plate heat exchanger 30 includes a refrigerant flow channel 31 and a water flow channel 32. The refrigerant flow channel 31 has a first end 31A and a second end 31B of the refrigerant flow channel. The plate heat exchanger 30 is connected to the refrigerant circulation loop of the water source machine through its refrigerant flow channel 31. The first end 31A of the refrigerant flow channel is connected to the liquid side stop valve 60 through a pipeline, and the electronic expansion valve 40 as described above is provided on the connecting pipeline between the first end 31A of the refrigerant flow channel and the liquid side stop valve 60. The first water flow switch S1 and the second water flow switch S2 are provided on the water inlet side of the water flow channel 32, and the disconnection value of the first water flow switch S1 is less than the disconnection value of the second water flow switch S2.

[0102] The four-way valve 20 has four ports, namely, the four-way valve port one 21, the four-way valve port two 22, the four-way valve port three 23, and the four-way valve port four 24. The four-way valve port one 21 is connected to the gas side stop valve 50, the four-way valve port two 22 is connected to the compressor discharge port 11, the four-way valve port three 23 is connected to the second end 31B of the refrigerant flow channel, and the four-way valve port four 24 is connected to the compressor suction port 12.

[0103] The first temperature sensor 70 is provided on the water inlet side of the water flow channel 32, and it is used to detect the water inlet temperature of the water flow channel when the water source machine heats, that is, the water source inlet temperature.

[0104] The second temperature sensor 80 is provided on the second end 31B of the refrigerant flow channel, and it is used to detect the refrigerant temperature flowing out of the refrigerant flow channel 31 when the water source machine heats, that is, the refrigerant temperature flowing out of the plate heat exchanger 30.

[0105] The first end of the bypass pipeline 90 is connected to the connecting pipeline between the four-way valve port two 22 and the compressor discharge port 11, the second end of the bypass pipeline 90 is connected to the connecting pipeline between the refrigerant flow channel 31 and the electronic expansion valve 40, and the electromagnetic valve 100 is provided on the bypass pipeline 90.

[0106] Different from the first embodiment and the second embodiment, in this embodiment, the outdoor unit further includes a gas-liquid separator 120 and an oil separator 130. The gas-liquid separator 120 is connected between the compressor suction port 12 and the four-way valve port four 24, and the oil separator 130 is connected between the compressor discharge port 11 and the four-way valve port two 22. The gas-liquid separator 120 separates the gas and liquid of the refrigerant to be introduced into the compressor suction port 12, prevents the occurrence of compressor liquid slugging phenomenon, and ensures the reliable operation of the compressor 10. The oil separator 130 is used to separate the lubricating oil from the high-pressure gaseous refrigerant discharged from the compressor discharge port 11 to ensure the safe and efficient operation of the unit.

[0107] In this embodiment, the control of the compressor 10, the electronic expansion valve 40, and the electromagnetic valve 100 by the controller is the same as that in the second embodiment, and will not be elaborated here.

[0108] Embodiment Four

[0109] Figure 9 Shows a schematic structural diagram of a water source machine according to Embodiment 4. Figure 10 Shows a schematic structural diagram of the outdoor unit of the water source machine according to Embodiment 4. As Figure 9 and Figure 10 shown, different from Embodiment 1, Embodiment 2 and Embodiment 3, in this embodiment, an oil return pipeline 140 is connected between the oil separator 130 and the gas-liquid separator 120, and a capillary tube 150 is connected to the oil return pipeline 140. The lubricating oil separated in the oil separator 130 flows back to the compressor 10 through the oil return pipeline 140, the capillary tube 150 and the gas-liquid separator 120, which can play a role in protecting the compressor 10; at the same time, since the oil separator 130 is on the high-pressure side and the gas-liquid separator 120 is on the low-pressure side, by setting the capillary tube 150, the loss of refrigerant capacity can be avoided.

[0110] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0111] The above is only the specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A water source machine, comprising an indoor unit and an outdoor unit, with a gas-side stop valve and a liquid-side stop valve connected therebetween, characterized in that, The outdoor unit includes: A compressor; A plate heat exchanger, which includes a refrigerant flow channel and a water flow channel. The first end of the refrigerant flow channel is connected to the liquid-side stop valve, and an electronic expansion valve is provided between the refrigerant flow channel and the liquid-side stop valve. A first water flow switch and a second water flow switch are provided on the water inlet side of the water flow channel, and the disconnection value of the first water flow switch is less than the disconnection value of the second water flow switch; A four-way valve, whose port 1 is connected to the gas-side stop valve, port 2 is connected to the compressor discharge port, port 3 is connected to the second end of the refrigerant flow channel, and port 4 is connected to the compressor suction port; A first temperature sensor, which is used to detect the inlet water temperature when the water source machine is in heating mode; A second temperature sensor, which is used to detect the refrigerant temperature at the outlet side of the plate heat exchanger when the water source machine is in heating mode; A controller, which is configured to: when the water source machine is in heating mode, when the detection value of the first temperature sensor reaches the upper limit value of the first preset water temperature, control the first water flow switch to detect; when the detection value of the first temperature sensor reaches the lower limit value of the first preset water temperature, control the second water flow switch to detect and adjust the refrigerant temperature at the outlet side of the plate heat exchanger based on the detection value of the second temperature sensor; when the detection value of the first temperature sensor reaches the lower limit value of the second preset water temperature, control the water source machine to stop; the second preset water temperature is less than the first preset water temperature.

2. The water source machine according to claim 1, wherein When the detection value of the second temperature sensor reaches the lower limit value of the first preset refrigerant temperature, the controller controls the compressor to prohibit frequency increase and at the same time controls the electronic expansion valve to prohibit valve closing; When the detection value of the second temperature sensor reaches the lower limit value of the second preset refrigerant temperature, the controller controls the compressor to force frequency reduction and at the same time controls the electronic expansion valve to force valve opening; When the detection value of the second temperature sensor reaches the lower limit value of the third preset refrigerant temperature and lasts for a certain period of time, the controller controls the water source machine to stop; When the detection value of the second temperature sensor reaches the upper limit value of the fourth preset refrigerant temperature, the water source machine enters the normal control stage; Wherein, the third preset refrigerant temperature is less than the second preset refrigerant temperature, the second preset refrigerant temperature is less than the first preset refrigerant temperature, the first preset refrigerant temperature is less than the fourth preset refrigerant temperature, the fourth preset refrigerant temperature is less than the inlet water temperature of the water flow channel, and the third preset refrigerant temperature is greater than zero degrees.

3. The water source machine according to claim 2, wherein The forced frequency reduction rate of the compressor is 1-3 Hz / second, and the forced valve opening rate of the electronic expansion valve is 5-15 steps / second.

4. The water source machine according to claim 1, wherein The outdoor unit further includes a bypass pipeline. The first end of the bypass pipeline is connected to the pipeline between port 2 and the compressor discharge port, and the second end of the bypass pipeline is connected to the pipeline between the refrigerant flow channel and the electronic expansion valve. An electromagnetic valve is provided on the bypass pipeline.

5. The water source machine according to claim 4, wherein A check valve is further provided on the bypass pipeline, and the check valve is located between the solenoid valve and the second end of the bypass pipeline.

6. The water source machine according to claim 4, wherein when the detection value of the second temperature sensor reaches the lower limit value of the fifth preset refrigerant temperature, the controller controls the solenoid valve to open intermittently until the detection value of the second temperature sensor reaches the upper limit value of the sixth preset refrigerant temperature, and then the solenoid valve closes; when the detection value of the second temperature sensor reaches the lower limit value of the seventh preset refrigerant temperature, the controller controls the solenoid valve to open intermittently, and at the same time the controller controls the compressor to prohibit frequency increase and the electronic expansion valve to prohibit valve closing; when the detection value of the second temperature sensor reaches the lower limit value of the eighth preset refrigerant temperature, the controller controls the solenoid valve to open intermittently, and at the same time the controller controls the compressor to force frequency reduction and the electronic expansion valve to force valve opening; when the detection value of the second temperature sensor reaches the lower limit value of the ninth preset refrigerant temperature and lasts for a certain period of time, the controller controls the water source machine to stop; wherein, the ninth preset refrigerant temperature is less than the eighth preset refrigerant temperature, the eighth preset refrigerant temperature is less than the seventh preset refrigerant temperature, the seventh preset refrigerant temperature is less than the fifth preset refrigerant temperature, the fifth preset refrigerant temperature is less than the sixth preset refrigerant temperature, the sixth preset refrigerant temperature is less than the inlet temperature of the water flow path, and the ninth preset refrigerant temperature is greater than zero degrees.

7. The water source machine according to claim 6, wherein the forced frequency reduction rate of the compressor is 1-3 Hz / second, and the forced valve opening rate of the electronic expansion valve is 5-15 steps / second.

8. The water source machine according to any one of claims 1-7, wherein the outdoor unit further includes a gas-liquid separator, and the gas-liquid separator is connected between the suction port of the compressor and port four of the four-way valve.

9. The water source machine according to claim 8, wherein the outdoor unit further includes an oil separator, and the oil separator is connected between the exhaust port of the compressor and port two of the four-way valve.

10. The water source machine according to claim 9, wherein a return oil pipeline is connected between the oil separator and the gas-liquid separator, and a capillary tube is connected to the return oil pipeline.

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